1. Field of the Invention
The present invention relates to a device for positioning bobbins with yarn packages, particularly before such bobbins are withdrawn from a textile spinning machine.
2. Description of the Related Art
Certain methods and devices have been developed for positioning cone-shaped bobbins in open end spinning machines.
When the machine has two conveyer belts, positioning is performed, e.g., by transferring the bobbins from one belt to the other, the bobbins being thus turned through 180.degree.. The bobbins are then delivered from the machine on only one belt. The advantage of this method is its easy practicability. Its disadvantage is that both belts must move to discharge the bobbins. This prolongs the time required to transfer the bobbins since all of the bobbins must be discharged on both belts together. When an automatic doffing device is used, a long delay is encountered.
In another known method of positioning bobbins, a device is used to determine the position of the bobbin on a single belt. Based on this determination, the bobbin is horizontally positioned by being lifted and turned through 180.degree.. This method can only be used with conical bobbins. Cylindrical bobbins cannot be similarly positioned because of the location of their yarn reserve.
The specified methods of positioning bobbins do not, in any case, secure the exact position of the bobbin relative to the tube, which is a function of yarn winding diameter.